package org.jujubeframework.util.security;

import lombok.AccessLevel;
import lombok.NoArgsConstructor;
import org.apache.commons.codec.binary.Base64;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import java.io.IOException;
import java.security.SecureRandom;

/**
 * des算法（加密、解密工具类）
 *
 * @author John Li
 */
@NoArgsConstructor(access = AccessLevel.PRIVATE)
public class DesUtil {
    private static final String DES = "DES";

    /**
     * Description 根据键值进行加密
     *
     * @param data
     * @param key  加密键byte数组。长度必须为8,16,32,64之一
     */
    public static String encrypt(String data, String key) throws Exception {
        byte[] bt = encrypt(data.getBytes(), key.getBytes());
        String strs = Base64.encodeBase64String(bt);
        return strs;
    }

    /**
     * Description 根据键值进行解密
     *
     * @param data
     * @param key  加密键byte数组.长度必须为8,16,32,64之一
     */
    public static String decrypt(String data, String key) throws IOException, Exception {
        if (data == null) {
            return null;
        }
        byte[] buf = Base64.decodeBase64(data);
        byte[] bt = decrypt(buf, key.getBytes());
        return new String(bt);
    }

    /**
     * 根据键值进行加密
     *
     * @param data
     * @param key  加密键byte数组
     */
    private static byte[] encrypt(byte[] data, byte[] key) throws Exception {
        // 生成一个可信任的随机数源
        SecureRandom sr = new SecureRandom();
        // 从原始密钥数据创建DESKeySpec对象
        DESKeySpec dks = new DESKeySpec(key);
        // 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
        SecretKey securekey = keyFactory.generateSecret(dks);
        // Cipher对象实际完成加密操作
        Cipher cipher = Cipher.getInstance(DES);
        // 用密钥初始化Cipher对象
        cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);
        return cipher.doFinal(data);
    }

    /**
     * 根据键值进行解密
     *
     * @param data
     * @param key  加密键byte数组
     */
    private static byte[] decrypt(byte[] data, byte[] key) throws Exception {
        // 生成一个可信任的随机数源
        SecureRandom sr = new SecureRandom();
        // 从原始密钥数据创建DESKeySpec对象
        DESKeySpec dks = new DESKeySpec(key);
        // 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
        SecretKey securekey = keyFactory.generateSecret(dks);
        // Cipher对象实际完成解密操作
        Cipher cipher = Cipher.getInstance(DES);
        // 用密钥初始化Cipher对象
        cipher.init(Cipher.DECRYPT_MODE, securekey, sr);
        return cipher.doFinal(data);
    }
}
